1. Field of the Invention
This invention relates to tools for attaching connectors to coaxial cables by compressing the connector in a direction parallel to the axis of the cable. More specifically, the present invention relates to axial compression tools capable of attaching different sizes of axial compression connectors to cable of correspondingly different diameters.
2. Description of Related Art
Coaxial cable is widely used to carry radio and television signals, digital data and the like. A major user of coaxial cable is the cable television industry, which uses coaxial cable to carry the signal from a central location to each subscriber.
To make the many connections required for the cable television network requires the installation of numerous coaxial cable connectors. To avoid any interruption in service, it is critical that the connectors be applied properly. Many problems with poor signal quality that require expensive service calls are the result of a connector that was initially installed incorrectly.
Coaxial cable connectors come in a variety of designs, and are attached in a correspondingly wide variety of ways with various tools. However, an increasingly popular connector design is secured to the prepared end of the coaxial cable by axially compressing the connector, i.e. by compressing the connector in a direction that is parallel to the longitudinal axis of the coaxial cable.
Connectors that are applied this way are available for different cable diameters and have heretofore required different tools for compressing them. U.S. Pat. No. 5,934,137 owned by the assignee of this application shows a widely used axial compression assembly tool, capable of rapid and reliable operation. However, that tool, like other competing designs, is intended to handle only a single connector size. Typically, an installer will carry one tool for attaching connectors to large diameter cable of the type used to distribute the signal from a central point to a neighborhood, and a second tool for attaching smaller connectors on smaller diameter cable used at each drop point to bring the signal into the subscriber""s home.
The present tool addresses the industry desire to reduce the number of cable installation tools that the installer must carry.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a compression assembly tool for axially compressing at least two different sizes of electrical connectors onto coaxial cables.
It is another object of the present invention to provide a compression assembly tool which allows the cable and compressed connector to be easily removed from the tool after the connector is compressed.
A further object of the invention is to provide a compression tool which maintains the axis of the coaxial cable in accurate alignment with the axis of the plunger.
It is yet another object of the present invention to provide a compression tool which is easy to use and which opens automatically, but which can be stored in the closed position.
A further object of the present invention is to provide a compression tool which can be easily adjusted.
The above and other objects and advantages, which will be apparent to those skilled in the art, are achieved in the present invention which is directed to, in a first aspect, a compression assembly tool for attaching first and second connectors of different sizes to the ends of corresponding first and second different cables. The compression assembly tool includes a body having an open portion defining a compression region for receiving the connectors when they are being attached to their corresponding cables.
A lever handle is pivotally attached to the body and drives a plunger in a longitudinal sliding motion relative to the body between an extended position and a retracted position. In the extended position the plunger axially compresses a connector placed into the compression region. In the retracted position the plunger moves out of the way and the compressed connector can be removed from the compression region.
The tool has at least two pairs of split base supports located at different distances from the plunger to accommodate different connectors. A first pair of split base supports is located a first distance from the plunger when the plunger is in the extended position. The first split base supports pivot on the body between an open position and a closed position and each of the first split base supports has an annular bearing surface of a first diameter corresponding to the diameter of the first cable.
A second pair of split base supports is located a second distance from the plunger when the plunger is in the extended position. The second distance is greater than the first distance to accommodate the length of the second longer connector. The second split base supports are also pivotally attached to the body for motion between an open position and a closed position. Each of the second split base supports has an annular bearing surface of a second diameter corresponding to the second cable. The first split base supports open sufficiently to move out of the way and accommodate the diameter of the second connector when the larger second connector is being compressed.
First and second springs operate to urge the first and second split base supports towards the closed position. The annular bearing surfaces of the first split base supports encircle the first cable when they are closed. In the closed position the first pair of split base supports provide annular bearing support for the end of the first connector opposite the plunger during compression. The annular bearing surfaces of the first split base supports allow the first cable to be removed when the first split base supports are in the open position. The annular bearing surfaces of the second split base supports operate in the same way to encircle the second cable when the second split base supports are in the closed position and provide annular bearing support for the back end of the second connector.
In another aspect of the compression assembly tool, at least one of the first split base supports and at least one of the second split base supports include a stop surface that contacts the body as the split base supports close. This brings the first and second split base supports into axial alignment with the plunger when the split base supports are closed. In the preferred design, all of the split base supports are identical, except for the diameter of the annular bearing surfaces, and all include a stop surface of this type.
The plunger is preferably driven by a link and includes a removable plunger tip that is threaded into the plunger. This allows the plunger tip to be longitudinally adjusted by rotating it relative to the plunger to adjust the distance between the plunger and the split bases and thereby adjust the amount by which the connectors are compressed. When a threaded adjustable plunger tip is used, a locking screw is provided to lock the plunger tip against rotation. The locking screw threads transversely into an end of the plunger to lock the plunger tip against rotation.
In yet another aspect of the invention, the compression assembly tool uses an O-frame to provide a light, but strong body structure. In still another aspect of the invention both of the pairs of first and second split base supports are pivotally attached to the body via a common pivot. The handle is provided with a handle spring mounted between the body and the lever handle for urging the lever handle away from the body. A releasable handle lock holds the lever handle towards the body when the tool is not in use.